The motivation and description are contained in the last patch in this set.
Will copy paste it here for convenience:
In order to evaluate write amplification factor (WAF) within the storage
stack it is important to know the number of bytes written to the
controller. The existing SMART log value of Data Units Written is too
coarse (given in units of 500 Kb) and so we add the SMART health
information extended from the OCP specification (given in units of bytes).
To accommodate different vendor specific specifications like OCP, we add a
multiplexing function (nvme_vendor_specific_log) which will route to the
different log functions based on arguments and log ids. We only return the
OCP extended smart log when the command is 0xC0 and ocp has been turned on
in the args.
Though we add the whole nvme smart log extended structure, we only populate
the physical_media_units_{read,written}, log_page_version and
log_page_uuid.
V1 changes:
1. I moved the ocp parameter from the namespace to the subsystem as it is
defined there in the OCP specification
2. I now accumulate statistics from all namespaces and report them back on
the extended log as per the spec.
3. I removed the default case in the switch in nvme_vendor_specific_log as
it does not have any special function.
Joel Granados (3):
nvme: Move adjustment of data_units{read,written}
nvme: Add ocp to the subsys
nvme: Add physical writes/reads from OCP log
hw/nvme/ctrl.c | 70 ++++++++++++++++++++++++++++++++++++++++----
hw/nvme/nvme.h | 1 +
hw/nvme/subsys.c | 4 +--
include/block/nvme.h | 36 +++++++++++++++++++++++
4 files changed, 103 insertions(+), 8 deletions(-)
--
2.30.2
